Gas burner



Feb. 14, 1961 D. c. WALLACE 2,971,577

GAS BURNER Filed Aug. 22, 1958 2 Sheets-Sheet 1 v- D N '3 N N Q Q N R.

INVENTOR. fia/v/ua C WALLACE ATTORNEYS.

Feb. 14, 1961 n. c. WALLACE 2,971,577

GAS BURNER Filed Aug. 22, 1958 2 Sheets-Sheet 2 I INVENTOR.

Dow/:40 C h ALZACE' United States Patent GAS BURNER Donald C. Wallace, Lakewood, Ohio, assignor to The Barber Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Aug. 22, 1958, Ser. No. 756,577

4 Claims. (Cl. 158106) This invention relates to fuel burners and more particularly to an improved gas burner especially adapted for use in furnaces or other heating apparatus.

In gas burners employed in heating furnaces or the like, multiple outlet devices have been proposed. In numerous types of burners it is also a usual practice to mix the fuel gas with a supply of primary combustion air and then, at the outlet of the burner nozzle, supply additional secondary combustion air. It is among the objects of the present invention to provide a multiple nozzle gas burner wherein the secondary air supply is delivered entirely around a substantially annular outlet for the mixture of gas and primary air, thus effecting complete combustion in a most efficient manner.

Other objects of my invention are the provision of an axial flow gas burner of compact and relatively inexpensive construction wherein the size of the flame may readily be controlled and wherein the ratio of primary to secondary air is established by the burner construction.

The above and other objects of my invention will appear from the following description of one embodiment thereof, reference being hadto the accompanying drawings in which:

Figure 1 is a vertical cross-sectional view of a complete burner unit embodying my improvements, taken substantially on line 11 of Figure 3;

Figure 2 is an end view of the burner illustrated in Figure 1, taken substantially on line 2-2 of Figure 1;

Figure 3 is an opposite end view of the burner of Figure 1, taken substantially on line 3-3 of Figure 1;

Figure 4 is a vertical cross-sectional view, taken substantially on line 44 of Figure 1;

Figure 5 is a vertical cross-sectional view, taken substantially on line 55 of Figure 1;

Figure 6 is a vertical cross-sectional view taken substantially on line 66 of Figure 1; and

Figure 7 is a detached illustrative view of one of the gas and air mixing tubes of the burner shown in Figures 1-6.

Referring to the drawings, the burner as illustrated includes a tubular housing, generally indicated at H, and having a fan enclosing section 1 at one end and a gas and air mixing section 2, of smaller diameter than said fan enclosure section, at the other end. The sections 1 and 2 are connected by a tapered intermediate section 3. An apertured end plate 4 extends across the open end of fan enclosing section 1 and is provided with three generally triangular air inlet openings 5. A rotary shutter member 6 is pivotally mounted on the inner face of end plate 4, as on pin 7, and carries circumferentially extending guard wires 8 which are movable with shutter member 6 and prevent foreign objects from entering the fan housing H through the inlet openings 5. A lock screw 9 is adapted to lock the shutter 6 in any circumferential position, and it will be observed that, by rotating shutter 6, the degree of opening of the 2,971,577 Patented Feb. 14, 1961 air inlets 5 may be increased or decreased to vary the total quantity of air and thus adjust the size of the flame.

An electric motor 10, generally cylindrical in form, is supported in the fan enclosing section 1 of housing H by radial mounting fins 11 (see Figure 6). The diameter of section 1 of housing H is preferably sufficiently larger than the diameter of motor 10 so that the cross-sectional area of the annular passage around motor 10 will be substantially equal to the effective cross-sectional area of the gas and air mixing section 2 of housing H.

A propeller type fan 12 is mounted on the shaft 13 of motor 10 and suitable electrical connections 14 supply current to motor 10 whereby, when the circuit is closed, the motor is driven and the fan 12 will draw air in through the inlet openings 5 and move same axially through the fan enclosing section 1 and the intermediate section 3 to and through the air and gas mixing section 2 of housing H.

Supported within the upstream (lefthand as seen in Figure 1) end of the air and gas mixing section 1 of housing H is an annular gas manifold 15 having a gas inlet connection 16 extending through the wall of housing H and adapted to be connected to any suitable source of supply of gas. Downstream of the gas manifold 15 is a baffle wall 17 secured to the inner face of section 2 of the tubular housing and extending thereacross. At the center of baffie wall 17 is a secondary air opening or metering passage 18, and the lower part of wall 17 is cut away to form a downwardly extending slot 19 through which the pilot light pipe, thermocouple leads, etc. may extend as will be later described.

Disposed around the inner circumference of section 2 of housing H are a plurality of venturi type gas and air mixing tubes generally indicated at M. These tubes are open at both ends, extend longitudinally of the housing H, and have their open inlet ends extending through and supported by the batlle plate 17. Coaxially disposed adjacent the inlet end of each of the mixing tubes M is a gas discharge jet or nozzle 20, each of which is connected to the interior of gas manifold 15 and is adapted to discharge gas into the inlet end of the adjacent mixing tube M.

As previously noted, the mixing tubes M are of the venturi type and have a center portion of reduced tapering cross-sectional area. As illustrated, these tubes are formed from round tubing of uniform cross-section. The inlet ends 22 of tubes M, arecircular in cross-section and are disposed closely adjacent the inner surface of tubular housing H. By a suitable stamping operation, the diameter of the intermediate portion of the mixing tubes M is reduced and shaped into venturi form, leaving outwardly extending fins or flanges 23 on the outer :face of the tubes. The outlet ends 24 of each of the tubes M are flattened to form arcuate elongated discharge openings which, when the series of tubes M are positioned in the burner structure, are disposed in end-to-end abutting relation (see Figure 3) and provide a substantially continuous discharge opening for the mixture of primary air and gas which opening extends circumferentially of section 2 of the tubular housing M but is spaced inwardly from the inner surface thereof. It will also be noted that the reduced diameter venturi throat portions of tubes M are spaced inwardly from the surface of mixing section 2 of the tubular housing H for purposes which will be later described.

In order to provide room for the installation of safety pilot means, there is no mixing tube M on the vertical center line of the housing H at the bottom thereof. The pilot light gas supply pipe 25 passes through the wall of housing H and extends through slot 19 in bafile wall 17 to the outlet end of the burner where it is provided with a downwardly directed pilot nozzle 26. Immedithe draft of air flowing ately below the nozzle 26 is a thermocouple unit 27 which is so electrically connected to the circuit of motor 10, and to suitable valve means in the gas supply line, that, if the pilot light at nozzle 26 goes out, the gas will be shut off and the motor stopped. A sheet metal shield member 28 overlies the pliot 26 and has a vertically extending rear wall 28 which protects the pilot 26 from through housing H. As seen in Figures 1 and 2, a nozzle support ring 31 extends from walls 28 around and is secured to the inner surfaces of burner outlets 24 and serves to support same.

The main igniting pilot light nozzle 29 is substantially centered at the discharge or outlet end of housing H, and its gas supply pipe 30 extends back through the secondary air passage 18 in baflie wall 17 and out through the wall of housing H to a suitable source of gas supply.

Disposed in the outlet ends 24 of the mixing tubes M are flame holder units 32 in the form of channel-.

shaped members slightly spaced from the inner walls of the outlet ends 24 as by projections formed on the outside of the flame holder. A function of these devices is to retard the velocity of the gas and primary air mixture adjacent the inner surface of the outlet ends 24 of the mixing tubes M and thus stabilize the flame.

When my improved burner is in operation, the motor is driven to rotate the fan 12 causing air to move axially through the housing H. This air passes through the central opening in the annular gas manifold 15 and,

due to the bafiie wall 17, a portion of the combustion air (the primary air) is caused to enter the inlet ends 22 of the mixing tubes M where it mixes with gas from the gas jets or nozzles 29. This mixture of primary air and gas passes through the venturi sections 21 of the mixing tubes and is discharged at the elongated flattened outlet ends 24 of tubes M.

Another part of the air moved by fan 12 through housing H passes through the passages 18 and 19 in baffle wall 17. This is the secondary combustion air, and part of it flows directly through and out of the end of the unit within the annular nozzle support ring 31. Another part of the secondary air will pass outwardly between the venturi sections of the adjacent mixing tubes M and pass along in the annular passage between the mixing tubes and the inner surface of section 2 of housing H. This flow is indicated by arrows in Figure l, and it will be observed that a part of the secondary air is discharged in an annular stream outside of the circumferentially extending discharge outlet for the primary air-gas mixture that is formed by the outlet ends 24 of tubes M.

Thus in my improved burner construction, the combustion air is moved axially Without substantial or abrupt change of direction and is caused to be divided so that a part of it is directly mixed with gas as primary combustion air, another part is directed inside of the annular burner outlet as secondary combustion air, and still another part surrounds and flows in an annular stream past the outside of the burner outlets 24. Thus, when the primary air-gas mixture flowing from the annularly arranged outlet ends 24 of the mixing tubes has been ignited, as by the pilot light 29, secondary air is supplied on all sides thereof, thus producing most uniform and efficient combustion conditions. By varying the air inlet opening into-the housing H by adjusting the shutter 6, the quantity and velocity of air delivered through the burner may be regulated. By this means the length of the flame at the burner end may be regulated to suit different conditions.

Although -I have described the illustrated embodiment of my invention in considerable detail, it will be understood that variations and modifications may be made in the specific form and arrangement of the parts making up my improved burner. Accordingly, I do not wish to be limited to the exact apparatus herein shown and described but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. A gas burner including a tubular housing, axial flow fan means disposed within said housing adjacent one end thereof, aplurality of open ended gas and air mixing tubes of venturi form having reduced area throat portions and being disposed around and closely adjacent to the inner surface of said tubular housing downstream of said fan means, a batfle wall extending across said housing adjacent the upstream ends of said mixing tubes, said baflie wall having a secondary air opening centered relative to said mixing tubes and the open upstream ends of said mixing tubes having a close fit in and extending therethrough, said gas and air mixing tubes extending from said baflie wall substantially to the other end of said tubular housing and having their outlet ends flattened and abutting each other whereby a substantially continuous discharge opening is provided extending circnmferentially of said tubular housing and spaced inwardly from the inner surface thereof, and gas outlet jets aligned with said open upstream ends of said mixing tubes and adapted to discharge gas thereinto and having their discharge ends spaced upstream of said throat portions of said mixing tubes.

2. A gas burner including atubular housing, means for creating an axial flow-of air through said housing, a plurality of open ended gas and air mixing tubes having center venturi throat portions and being disposed around the inner surface of said tubular housing, a baflie wall extending across said housing adjacent the upstream ends of said mixing tubes, said baffle wall having a central secondary air opening and said mixing tubes having a close fit in and extending therethrough, and gas outlet jets aligned with said open upstream ends of said mixing tubes and adapted to discharge gas thereinto, said center venturi throat portions of said mixing tubes being spaced circnmferentially from'each other and spaced radially I inwardly from the inner surface of said tubular housing,

thereof whereby secondary combustion air from said central secondary air opening in said baifle wall emerges from said tubular housing on both the inside and outside of said substantially continuous discharge opening formed by said outlet ends of said mixing tubes.

3. A gas burner including a tubular housing, axial flow for means disposed within said housing adjacent one end thereof, a plurality of open ended gas and air mixing tubes of venturi form disposed around the inner surface of said tubular housing downstream of said fan means, a bafiie Wall extending across said housing adjacent the upstream ends of said mixing tubes, said baffle wall having a central secondary air opening and the open upstream ends of said mixing tubes having a close fit in and extending therethrough, and an annular gas manifold in said tubular housing upstream of said upstream ends of said mixing tubes and having gas outlet jets aligned with said open upstream ends of said mixing tubes and adapted to discharge gas thereinto, said mixing tubes having center venturi throat portions spaced inwardly from the inner surface of said tubular housing, the open outlet ends of said mixing tubes being flattened and disposed in abutting relation to each other whereby a substantially continuous discharge opening is provided extending circnmferentially of said tubular housing and spaced inwardly from the inner surface thereof whereby secondary combustion air from said central secondary air opening in said baflFle wall emerges from said tubular housing n both he in ide and outside of said substantially continuous discharge opening formed by said abutting outlet ends of said mixing tubes.

4. A gas burner including a tubular housing, axial flow fan means disposed within said housing adjacent one end thereof, a plurality of open ended gas and air mixing tubes of venturi form disposed around the inner surface of said tubular housing downstream of said fan means, a bafiie wall extending across said housing adjacent the upstream ends of said mixing tubes, said bafiie wall having a central secondary air opening and the open upstream ends of said mixing tubes having a close fit in and extending therethrough, an annular gas manifold in said tubular housing upstream of said upstream ends of said mixing tubes and having gas outlet jets aligned with said open upstream ends of said mixing tubes and adapted to discharge gas thereinto, said mixing tubes haw ing center venturi throat portions spaced inwardly from the inner surface of said tubular housing, the open outlet ends of said mixing tubes being flattened and disposed in abutting relation to each other whereby a substantial- 1y continuous discharge opening is provided extending circumferentially of said tubular housing and spaced inwardly from the inner surface thereof whereby secondary combustion air from said central secondary air opening in said bafiie wall emerges from said tubular housing on both the inside and outside of said substantially continuous discharge opening formed by said abutting outlet ends of said mixing tubes, and adjustable means disposed upstream of said fan means for varying the opening at said one end of said tubular housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,548,316 Higgins Aug. 4, 1925 1,753,962 Lonergan Apr. 8, 1930 1,911,760 Lonergan May 30, 1933 2,196,282 Voorheis Apr. 9, 1940 2,263,170 Haedike Nov. 18, 1941 2,627,307 Westling Feb. 3, 1953 FOREIGN PATENTS 42,768 Austria June 25, 1910 

